<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Redux Demo</title>
</head>
<body>
  <button id="add_button">添加</button>
  <button id="clear_button">清除</button>
  <code>
    <pre id="displayer"></pre>
  </code>
</body>
</html>
